Hi guys, been out of the hardware game for a while so I would appreciate any input.

What do y'all think would be the best upgrades for the money for my sig rig? My budget is about $700. I mainly play SC2 and D3, with some LoL and IL-2 mixed in. Maybe the occasional FPS if anything intriguing comes out.

If you are very budget concious, a GTX 550 ti is pretty good if you don't need a incredibly high detail. It can play Metro 2033 on medium pretty well. It also gave me about a 10% overclock at the stock voltage. If you are looking to spend more, get a GTX 560 ti or GTX 480.
I would recommend a core i5 for the CPU, or core i3 if the i5 is too expensive.
See if you can try to fit an SSD boot drive into your budget, and use your old hard drive as a storage drive.

Thanks for the response y'all. I don't need a case (though that Fractal Core 1000 is tickling my fancy) or any other peripherals except maybe OS, but I think I can get that for cheap through school.
Right now I'm thinking 3570k+ Z77+ maybe an m4 if I can hold off on the GPU for a little while.